Quiet Twitch Chat by fcfcch

This addon lets you block/filter specified users from twitch chat so that their messages will not show up on your side.

--- Hide messages mentioning an account ---
Scroll down in the popup to Hide messages mentioning, enter a login such as Sample_user or @Sample_user, and click Add. Several names can be separated by spaces or commas. Matching messages disappear immediately, including new messages as they arrive.

A match anywhere in the message hides the whole message, not just the name.
Names are case-insensitive and exact: @Sample_user does not match @sample_userm. Add both logins if you want both filtered.
The author block list and mention-filter list are independent. Mention filtering does not automatically block messages written by that account.
Native Twitch and 7TV styled mentions are supported, including 7TV mentions whose @ sign is hidden by its settings or whose display name is localized.
Quoted reply text, sender labels, badges, and rendered web links are excluded from plain-text mention matching. This filters explicit mentions; it does not follow a thread's later messages if they have no matching mention.
Use Remove beside a mention filter to restore those messages. Pausing filtering restores both author-blocked and mention-filtered messages.
For live streams, enable Also filter live chat. VODs work with it off.
The filter updates existing messages immediately and handles newly loaded chat as playback continues or you seek. Alt-click a message author's name to block that account; an Undo button appears briefly. If your Linux window manager intercepts Alt-click, add the name through the popup instead.

Unblock restores that user's currently loaded messages. Turn off Filter chat to temporarily restore everything. Turn on Also filter live chat to use the same list in live streams. The default is replay only.